申请人:ELI LILLY AND COMPANY
公开号:EP0038626A1
公开(公告)日:1981-10-28
A process is described for removing the p-nitrobenzylester protecting group from a cephalosporin 4-carboxylic acid pNB ester and thereby liberating the free cephalosporin 4-carboxylic acid; characterized in that the p-nitrobenzylester is electrolytically reduced in an acidic liquid medium comprising from about 0 to about 50%water, an acid having a pKa determined in water of 0 or below, the amount of said acid being at least four moles per mole of the compound to be reduced, and an organic solvent substantially inert to electrolytic reduction, at the working electrode of an electrolytic cell, said working electrode substantially comprising carbon, mercury, tin, aluminium, silver, copper, lead, chromium, zinc, nickel or cadmium, at a temperature from about 0°C. to about 75°C., at a potential in a range from about the potential (A) of the initial onset of current flow of the first reduction to about the potential (B) of the initial onset of current flow of the second reduction.
描述了一种从头孢菌素 4-羧酸对硝基苄酯中去除对硝基苄酯保护基团,从而释放游离头孢菌素 4-羧酸的工艺;其特征在于,对硝基苄酯在酸性液体介质中进行电解还原,该介质包括约0至约50%的水、在水中测定的pKa为0或以下的酸,所述酸的量为每摩尔待还原化合物至少4摩尔、和对电解还原基本惰性的有机溶剂,在电解槽的工作电极上,所述工作电极基本由碳、汞、锡、铝、银、铜、铅、铬、锌、镍或镉组成,温度约为 0°C.至约 75°C、电位范围从第一还原电流初始开始时的电位 (A) 到第二还原电流初始开始时的电位 (B)。